Hot tea, coffee linked to higher risk of oesophageal cancer — Study

People who regularly drink very hot tea or coffee may face a significantly higher risk of developing oesophageal cancer, a study has found.

The researchers found that people who preferred their beverages very hot had more than three times the risk of developing oesophageal squamous cell carcinoma (SCC) compared with those who preferred warm drinks.

The study, involving nearly 980,000 middle-aged adults in the United Kingdom, was published in the International Journal of Cancer.

Oesophageal cancer affects the tube that carries food and drinks from the mouth to the stomach. Oesophageal SCC is the most common form of the disease globally.

How hot is too hot?

The International Agency for Research on Cancer (IARC), the cancer research arm of the World Health Organisation (WHO), classifies beverages consumed at temperatures above 65°C as “probably carcinogenic to humans”.

For the new study, researchers used data from participants in the UK Biobank and Million Women Study.

Participants reported how hot they usually preferred their tea, coffee and other hot drinks, choosing from “very hot”, “hot” and “warm”. They also reported whether they consumed fewer than six or at least six hot drinks each day.

Over the follow-up period, 2,348 cases of oesophageal cancer were recorded among the participants.

The analysis showed that the risk increased with the preferred temperature of the drinks.

Those who preferred hot beverages had almost twice the risk of oesophageal SCC compared with people who preferred warm drinks, while the risk among those who preferred very hot drinks was more than three times higher.

The researchers also found that consumption frequency was associated with risk.

After taking temperature into account, participants who drank six or more hot beverages daily had a 71 per cent higher risk of oesophageal SCC than those who consumed fewer than six.

Why temperature may matter

Keren Papier, a senior nutritional epidemiologist at the University of Oxford and lead author of the study, said the findings add to existing evidence linking very hot beverages with oesophageal cancer.

Previous research had largely focused on populations in South America, Asia and the Middle East, where hot-drink consumption patterns differ from those in Western countries.

Ms Papier said the new findings provide evidence from typical drinking habits in the UK, where tea and coffee are commonly consumed.

The researchers said the association was not altered by whether participants added milk to their drinks, as long as the beverage remained hot.

Also sharing his thoughts, Ian Johnson, an emeritus fellow at the Quadram Institute in England, said damage to cells lining the oesophagus and inflammation caused by hot liquids could provide a possible explanation for the association.

He advised people to allow hot drinks to cool before consuming them.

Study does not prove cause

The researchers cautioned that the study did not establish that hot drinks directly cause oesophageal cancer.

One limitation was that participants did not measure the actual temperature of their beverages. Instead, they described them according to their own perception of how hot they were.

Muy-Teck Teh, a professor of molecular oral oncology at Queen Mary University of London, said differences in people’s sensitivity to heat meant the findings should be interpreted as an association rather than proof that hot beverages cause the cancer.

The researchers said allowing drinks to cool, adding milk or cold water, or simply waiting before drinking could reduce exposure to high temperatures.

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Global burden

Oesophageal cancer remains a major global health concern.

According to the IARC, about 604,000 new cases and 544,000 deaths from oesophageal cancer were recorded globally in 2020.

The agency projects that annual cases could approach one million by 2040, representing an increase of more than 50 per cent.

However, the researchers noted that the absolute risk of developing oesophageal cancer remains relatively low.

The study therefore suggests that for people who enjoy tea or coffee, allowing the beverage to cool before drinking may be a simple precaution against prolonged exposure to very hot liquids.